While, the negative impacts of increasing ocean acidification on clams, scallops and other bivalves the biological basis is still unclear, “legacy effect” of early CO2 explosure can play a significant role in bivalve population dynamics.

NCCOS-funded researchers performed a series of experiments to look at the days-to-months impacts of carbon dioxide (CO2) on the larvae of northern quahogs (Mercenaria mercenaria) and Atlantic bay scallops (Argopecten irradians), and found early that exposure of larvae (≤ 4 days old) to high CO2 definitely killed more larvae than larvae first exposed at an older age.

The researchers also found larva exposure to elevated CO2 during the first four days of development resulted in lower shell calcification rates which contributed to higher mortality. For the larvae that did survived the early exposure to high CO2, they grew to smaller-size adults compared to the adults of larvae that did not experience early exposure to high levels of CO2.